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Tutorial update due to some changes in GPy

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Nicolas 2013-02-21 10:23:18 +00:00
parent fc86b8e1ac
commit 949f363020
1 changed files with 8 additions and 4 deletions
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12
doc/tuto_kernel_overview.rst
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@ -28,9 +28,8 @@ should return::
Name | Value | Constraints | Ties
-------------------------------------------------------
rbf_variance | 1.0000 | |
rbf_lengthscale | 1.0000 | |
rbf_variance | 0.7500 | |
rbf_lengthscale | 2.0000 | |
.. figure:: Figures/tuto_kern_overview_basicdef.png
:align: center
@ -50,7 +49,12 @@ On the other hand, it is possible to use the `sympy` package to build new kernel
Operations to combine kernel
============================
In ``GPy``, kernel objects can be combined with the usual ``+`` and ``*`` operators. ::
In ``GPy``, two kernel objects can be added or multiplied. In both cases, two kinds of operations are possible since one can assume that the kernels to add/multiply are defined on the same space or on different subspaces. In other words, it is possible to use two kernels :math:`k_1,\ k_2` over :math:`\mathbb{R} \times \mathbb{R}` to create
* a kernel over :math:`\mathbb{R} \times \mathbb{R}`: :math:`k(x,y) = k_1(x,y) \times k_2(x,y)`
* a kernel over .. :math:`\mathbb{R}^2 \times \mathbb{R}^2`: :math:`k(x,y) = k_1(x_1,y_1) \times k_2(x_2,y_2)`
multiplied combined with the usual ``+`` and ``*`` operators. ::
k1 = GPy.kern.rbf(1,variance=1., lengthscale=2)
k2 = GPy.kern.Matern32(1,variance=1., lengthscale=2)